Modelling and Simulation of PEM Fuel Cells With CO Poisoning

A polymer electrolyte membrane (PEM) fuel cell has been analyzed by applying the conservation principle to the gas channels, electrode backings, catalyst layers and polymer electrolyte. The conservation equations used are conservation of species, momentum and energy and the Nernst-Planck equation in the electrolyte. Oxygen reduction at the cathode is modeled using the Butler-Volmer equation while the adsorption, desorption and electro-oxidation of hydrogen and CO at the anode are modeled by the Tafel-Volmer and “reactant-pair” mechanism, respectively. Comparison of the anode electrochemical kinetics model to experimental data indicates that CO adsorption kinetics are Temkin. One-dimensional simulation of a PEM fuel cell operating with reformate fuel gas indicates an optimum operating pressure. Preliminary two-dimensional simulation verifies the one-dimensional assumption for mass transfer but indicates that a two-dimensional analysis is necessary for the catalyst layer.